This disclosure is generally related to Code Division Multiple Access (CDMA) and Worldwide Interoperability for Microwave Access (“WiMAX”) technologies. In one or more embodiments, this disclosure is directed to a system and method useful for improving the utilization of WiMAX systems that operate with dual-mode WiMAX/CDMA devices, in particular, dual-mode WiMAX/CDMA devices operating in an Evolution-Data Optimized or Evolution-Data only (“EV-DO”)/CDMA and WiMAX overlay networks.
EVDO, or Evolution Data Only/Evolution Data Optimized, is a 3G mobile broadband technology used by various wireless carriers such as Verizon, Sprint, and Alltel that provides typical speeds of 600-1400 kbps download (with bursts up to 2000 kbps) and 500-800 kbps upload by wireless transmission. EVDO is a telecommunications standard for the wireless transmission of data through radio signals, typically for broadband Internet access. The resulting Internet connection may be shared with multiple computers using a 3G router, similar to a conventional broadband connection. It is standardized by 3rd Generation Partnership Project 2 (3GPP2) as part of the CDMA2000 family of standards, and has been adopted by many mobile phone service providers around the world—particularly those previously employing CDMA networks.
WiMAX networks are not yet as widespread as CDMA and EDVO networks, however several conventional dual-mode WiMAX/CDMA devices exist. For such conventional WiMAX/CDMA dual-mode devices, the priority is always to look for the WiMAX system first. If a WiMAX system is not available, then the device looks for the EVDO system. If the EVDO system is not available, then the device looks for the CDMA system. Furthermore, such conventional dual-mode devices are required to return to the WiMAX system as soon as possible, if it is not currently served by a WiMAX system. As a result, some conventional dual-mode devices are required to constantly scan for a WiMAX system even if the device is receiving service from the EVDO or CDMA systems. Since current WiMAX coverage is minimal compared to currently available CDMA and EVDO coverage, there presently is a high likelihood that the device will waste processor time and battery drain to scan for the WiMAX system, which does not yet exist in most regions. Consequently, other conventional dual-mode devices are designed in such that the device must stay in the EVDO system and/or CDMA system once it moves outside WiMAX coverage, and does not allow return to the WiMAX system even if WiMAX becomes available thereafter. As a result, the device cannot take full advantage of the benefit that WiMAX networks have to offer in terms of data throughput and latency. Further, concern for battery life greatly limits the usability of the WiMAX system in conventional dual-mode devices, and therefore adversely impacts system performance and the user's experience.
What is needed is an apparatus and method that seamlessly allow a dual-mode CDMA/WiMAX device to transition between CDMA and WiMAX modes of operation. What is even further needed is an apparatus and method that allow a dual-mode CDMA/WiMAX device to seamlessly transition back and forth between CDMA and WiMAX modes of operation while reducing battery drain as compared to conventional dual-mode devices.